The present invention concerns a method of feeding substantially rectangular laundry articles to a laundry processing apparatus, such as an ironing roller, comprising alignment of the laundry article to a predetermined angle with respect to the direction of feed of the laundry article on a conveyor face on which the laundry article is conveyed with the rear edge stretched, seen with respect to the direction of feed, as well as lateral displacement of the laundry article on the conveyor face to a desired position transversely to the direction of feed. The invention also concerns an apparatus for performing the method.
These apparatuses are primarily used in big laundries in which they are used for smoothing and spreading large laundry articles, such as sheets, table-cloths, slips for eiderdowns, etc. for subsequent insertion of the laundry article into e.g. an ironing roller, it being important that these feeding devices spread and smooth the laundry articles effectively so that undesired creases will not occur after the ironing roller. Most frequently, the laundry articles are inserted into the apparatus by a laundry article being taken from a pile of laundry articles in a wrinkled state and optionally wet or damp, following which the laundry article is inserted into the machine, which subsequently processes the laundry article so that it can be transferred to e.g. an ironing roller in a spread and smoothened state.
Even though the laundry article is thus transferred to an optional ironing roller in a spread and smoothened state, unintentional creases in the laundry article may occur, however, after the ironing roller, if the laundry article is inserted askew into the ironing roller. These unintentional creases are produced in that, in this case, the ironing roller first pulls a corner of the laundry article forwardly, thereby forming creases on the laundry article. It is therefore important e.g. in connection with such ironing rollers that the laundry article is oriented such that the entire one edge of the laundry article is moved into the ironing roller approximately in parallel with the axis of rotation of the ironing roller.
Therefore, feeders are frequently provided with a device capable of orienting the laundry article such that when inserted into a subsequent optional ironing roller the laundry article has the desired orientation.
Numerous proposals for the construction of devices capable of performing the above-mentioned processes are known today. Thus, EP Patent Application 266 820 discloses a feeder comprising a roller capable of rotating about its own axis, the laundry article being so positioned across said roller as to extend down on both sides of the roller. The laundry article will then frequently be disposed askew on the roller, which is therefore adapted so as to be twistable about its longitudinal axis such that the laundry article may be aligned with respect to the roller. This alignment takes place by positioning the laundry article with respect to a plurality of optical sensors arranged in a horizontal plane with respect to each other so that these can detect an edge on the part of the laundry article which hangs down on one side of the roller. The roller can then be rotated and twisted in sequence, so that the edge of the laundry article precisely covers the row of optical sensors, said laundry article having thereby been aligned with respect to the feed direction of the roller.
Further, EP Patent Application 424 290 discloses a feeder having a short and wide conveyor belt across which the laundry article is hung so as to hang down on each side of the conveyor belt. Sensors are provided here too, detecting the position of the rear edge of the laundry article on the conveyor belt with a view to aligning the laundry article with respect to this conveyor belt. In this device, the alignment takes place by retaining the part of the laundry article hanging down on one side, while causing the laundry article to be moved with respect to the conveyor belt. This is effected by pressing an elongate rod toward the laundry article between the location where the laundry article is retained and the conveyor belt, whereby the laundry article is displaced on the conveyor belt, thereby making it possible to align the laundry article with respect to the conveyor belt.
In certain situations, e.g. when a folding-up machine capable of automatically folding-up the laundry articles is mounted after the ironing roller, it is moreover important that the laundry articles are positioned precisely in a lateral direction with respect to the direction of feed of the laundry article prior to optional folding-up so that the folding-up will be neat and uniform. For this purpose, there are folding-up machines which can displace the laundry article transversely prior to the folding-up. However, these folding-up machines require that the laundry article is displaced transversely before the folding-up is begun, which reduces the production rate of these machines. It is therefore desirable that such transverse displacement can be performed already in the feeder.
In both of the above-mentioned known devices the laundry article is inserted in that the laundry article is pulled from the side across the roller or the conveyor belt by a gripper, thereby enabling initial positioning of the laundry articles on the roller or the conveyor belt. However, the subsequent alignment of the laundry article on the roller or the conveyor belt may cause the initial positioning to be destroyed.
Accordingly, the object of the present invention is to provide a method of feeding and a machine for performing this method, by means of which the lateral positioning may be performed precisely in a simple manner.